This invention relates to combinations of (a) human gamma interferon (IFN-.gamma.), sometimes referred to as human immune interferon, with (b) synthetic abbreviated leukocyte interferon (IFN-.alpha.), which features a "sub-segment" defined as delta-4- alpha-2 (Bgl II-1) derived from an alpha-2 sequence that is joined to a segment defined as (Bgl II) alpha-1 derived from an alpha-1 sequence, which combinations display greater antiproliferative effects against human tumor cells and greater antiviral activity than could be expected from their individual activities.
There are a number of interferon hybrid made by recombinant techniques wherein two or more leukocyte interferon segments are combined by use of now standard recombinant DNA methods. Such hybrid are disclosed in U.S. Pat. Nos. 4,456,748 and 4,414,150 as well as in European Patent Application Publication No. 0051873, (May 19, 1982) and Weck et al., Nucleic Acids Research 9, 6153, (1981). However, there is no disclosure of a delta-4 .alpha.-interferon, i.e. one missing the first 4-amino acids.
European Patent Application Publication No. 0107498, (Oct. 24, 1983) discloses combinations of gamma interferon and, inter alia, "hybrid interferons" such as those disclosed in Weck et al and European Patent Application Publ. No. 00518731 as displaying "synergistic" biological activity as evidenced by antiproliferative effects against the human melanoma cell line Hs294T. However, there is no disclosure of a delta-4 hybrid.
European Patent Application Publication No. 0146903, (July 3, 1985) discloses a synthetic abbreviated interferon which exemplifies the preferred interferon hybrid suitable for use in this invention, i.e. delta-4 alpha-2 (Bgl II-1) derived from an alpha-2 sequence that is joined to a segment defined as (Bgl II) alpha-1 derived from an alpha-1 sequence.